The invention relates to an apparatus for shielding high frequency electrical and electromagnetic waves with respect to lines and groups of lines passed through a tight wall lead in. The invention comprises a pressure-resistant frame to be fixed to the wall entrance, the free space between the individual lines of the group and the frame being completely filled by modular, superimposed and juxtaposed, completely or partly elastic fitting pieces. A quantity thereof corresponding to the number of lines is in each case formed from two parts, provided with recesses emanating from their contact surfaces and adapted as regards shape and size to the cross-section of a particular line and, with the remaining fitting pieces, are under the action of a pressure acting in the frame plane, through which they are held in tight engagement with the lines and the frame inner wall.
If in known lead-ins of this type, the lines are to be shielded against high frequency electrical or electromagnetic waves in the vicinity of the lead-in, it is necessary to join the metal shield of the lines with a metal and preferably copper plate, which covers and is joined to the frame. This assembly procedure is expensive from the labor standpoint.
If the lines passed through the frame have to be supplemented or replaced, it is always necessary to break the connection between frame and metal plate and between metal plate and lines. After fitting the new lines, the appropriate metal plate must again be tightly connected with the line shields and with the lead-in frame.